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VB6 Program using MSComm started failing in Windows 7 this week

Hello All,

I have a VB6 program which uses MSComm to do RS232 communications to a radio
transceiver. Operation on Win 7 and XP has been very stable until this week. We
started noticing that on Win 7 systems, commands sent to the MSComm Port
sometimes never get to the radio or there are larger than before delays. This
happens on two different systems at different locations. The program still
operates normally on Win XP.

I am wondering if a recent Windows Update on Win 7 might have altered the MSComm
Control or the virtual Comm Ports. I noticed that yesterday when I launched the
Visual Basic Development System, there were numerous warnings about Registry
connections and several Controls used in the program were not loaded.
Fortunately, after exiting the Develop Environment and starting again, the
Controls all loaded.

Has anyone seen evidence that Microsoft has broken VB6 programs on Win 7?
Thanks. -ko6no-
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Re: VB6 Program using MSComm started failing in Windows 7 this week

I just posted a similar problem with the MS Common Controls set. When I try to open a new project and add the component, the 'apply' command button generates a 'File not found' error - although file is clearly in folder and registered correctly.

I just opened a new project in VB6, and added a MSCOMM component to the project. This DID work correctly. But I can't add a MS Common Control 6.0 (toolbars and image lists). This generates 'file not found' error.

Re: VB6 Program using MSComm started failing in Windows 7 this week

For what it's worth, my system did have W7 SP1 installed before the program was compiled. I don't know about the user at the other location. What I found was that there were increased latencies in the MSComm transactions. I managed to add some adaptive delays to my I/O routines to deal with it. Since then, the problems with MSComm have settled down. Thanks for the replies. -ken-
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Re: VB6 Program using MSComm started failing in Windows 7 this week

Sorry. I ddn't understand that dglienna meant VB6 SP1. I did install one or more Service Packs for VB6 when I installed it on Win 7. I can't tell from the version info in Visual Studio which SP is installed. The Windows record of installed programs doesn't show the upgrades or service packs for VB6. -ko6no-
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Re: VB6 Program using MSComm started failing in Windows 7 this week

Originally Posted by ko6no

Sorry. I ddn't understand that dglienna meant VB6 SP1. I did install one or more Service Packs for VB6 when I installed it on Win 7. I can't tell from the version info in Visual Studio which SP is installed. The Windows record of installed programs doesn't show the upgrades or service packs for VB6. -ko6no-
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In the VB6 IDE you go to help about and it will tell you which SP is installed. You should have SP6 installed under windows 7, I think there are some issue with any of the older service packs in windows 7